|
|
08-04-2016, 06:32 AM
|
#1
|
Senior Member
Join Date: Dec 2011
Location: Logan Indiana (Near Cincinnati Ohio)
Posts: 755
|
Surging Onan 12.5 diesel genset
Hi all,
Curious if anyone has had and had corrected a surging 12.5 Quiet Diesel genset?
Mine is at 2600 hours and has been great, came home from a trip last week and it was hunting just a little, almost hard to even hear it but I do see it in the voltage levels (up and down voltages). I have taken the covers all the way off, replaced the front end bearing, brushes, cleaned the slip rings, new cooling belt, new fuel filter, cleaned AC connections, checked for leaks, oil level, obvious defects and induction air cleaner...ect
Basically nothing found on google about it. Lots of info out there about gas generators surging.
I have the 3 cylinder Isuzu engine.
Any input appreciated.
Thanks
Windecker
|
|
|
|
Join the #1 RV Forum Today - It's Totally Free!
iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!
You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!
|
08-05-2016, 08:43 AM
|
#2
|
Senior Member
Monaco Owners Club
Join Date: Jan 2012
Location: .
Posts: 789
|
I was hoping you would get some help here, as we have a 12.5 also but do not have that problem. Just looking for info too.
__________________
|
|
|
08-05-2016, 08:48 AM
|
#3
|
Senior Member
Join Date: Jul 2014
Posts: 35,349
|
When you changed the fuel filter, was it full ?
If it's pulling air in before the pump, you can get a surge.
If you run it under a heavy load, it should struggle to maintain speed of its a fuel problem.
|
|
|
08-05-2016, 11:18 PM
|
#4
|
Senior Member
Monaco Owners Club
Join Date: Aug 2011
Location: Wherever we are
Posts: 389
|
Had the exact problem last year on our 10KW Onan. The Actuator Speed Control had failed. p/n 150-2700. $332.40. Labor $536. Work done at Cummins Rocky Mountain in Avondale (Phoenix) AZ. Their Onan specialist is very good.
Cheers,
__________________
Bob Covey
Home: 2003 Monaco Executive 43 SDDS, ISM
|
|
|
08-16-2016, 03:45 PM
|
#5
|
Senior Member
Join Date: Dec 2011
Location: Logan Indiana (Near Cincinnati Ohio)
Posts: 755
|
Surging
Thanks,
The filter change had no affect and loaded or unloaded did not matter either except that it seemed to happen more after a cold start following getting to temperature (meaning it did not surge until it had warmed up a little, loaded or unloaded).
Thanks
Windecker
Quote:
Originally Posted by twinboat
When you changed the fuel filter, was it full ?
If it's pulling air in before the pump, you can get a surge.
If you run it under a heavy load, it should struggle to maintain speed of its a fuel problem.
|
|
|
|
08-16-2016, 04:00 PM
|
#6
|
Senior Member
Join Date: Dec 2011
Location: Logan Indiana (Near Cincinnati Ohio)
Posts: 755
|
Actuator
Thanks for the heads up.
Actually, when I was checking things out I had pulled the electrical connectors off of the Governor actuator (maybe the same thing?) to check the connections and resistance. Seems to me it said it should be between 2.7 and 2.8 ohms. My Fluke showed 3.0 consistently. I have to admit, only .2 ohms off of spec on a simple crudely wired two wire relay looking thing seemed pretty close.
I plugged it back in and it has ran perfectly since. Only have about 6 hours on it now but has been perfect. Loaded and unloaded has been right on.
I am thankful because as most of us know, generators are not easily worked on and most of the time you have to leave your coach somewhere for who knows how long...
Hope that is the last time I see the issue but time will tell. I will remember this advice though, thanks.
Windecker
Update, I just found that 150-2700 actuator in the parts manual that you replaced, yup, that was it. I know where to go if this happens again
Quote:
Originally Posted by bobcovey
Had the exact problem last year on our 10KW Onan. The Actuator Speed Control had failed. p/n 150-2700. $332.40. Labor $536. Work done at Cummins Rocky Mountain in Avondale (Phoenix) AZ. Their Onan specialist is very good.
Cheers,
|
|
|
|
02-01-2017, 11:04 PM
|
#7
|
Senior Member
Join Date: Oct 2013
Posts: 245
|
Hey Windecker - any more issues with the generator surging? mine is doing the same thing - just hunting ever so slightly - after it has run awhile and is really warmed up. seems worse with a light load. I changed the fuel filter - and the pump (boy that was fun), checked lines, checked flow - after reading this thread I also checked the connections and resistance at the actuator - all check good... 10.0 HDCAA
Thanks,
Kurt.
__________________
99 Executive 38 M11 450
|
|
|
02-03-2017, 05:32 AM
|
#8
|
Senior Member
Join Date: Dec 2011
Location: Logan Indiana (Near Cincinnati Ohio)
Posts: 755
|
Happy for me, no, I have not had any further issues. Now to be fair, I only have maybe 40-50 more hours on it since the issue but things have been well.
If it happens to me again I will start by cleaning the connections at the regulator again and if it still continues I would replace it.
I wish I could help further but I am not a diesel mechanic and these generators seem to have black magic in them for whatever reason LOL.
Good luck and let me know if you figure it out, others will benefit.
Will
|
|
|
02-03-2017, 11:04 PM
|
#9
|
Senior Member
Join Date: Oct 2013
Posts: 245
|
Thanks Will, maybe I'll clean the slip rings, check the brushes etc. It only does it when thoroughly warmed up, and definitely is worse / more frequent under a light load. Don't really want to change the control unit at $800! when I checked the actuator I got the same .2 error you did... but then my old MAC tools meter shows .2 with the leads touching so I figure its right there. I had a guy tell me I need to blow the carbon out of the spark arrestor - and I found some discussions on that topic - but I can't see that causing the problem, and it sounds like a mess, so that will be my last resort - right before the board. probably won't get to it for a while but I'll check back in when I do.
Thanks again,
Kurt.
__________________
99 Executive 38 M11 450
|
|
|
02-05-2017, 08:07 AM
|
#10
|
Senior Member
Join Date: Dec 2011
Location: Logan Indiana (Near Cincinnati Ohio)
Posts: 755
|
Surging
Kurt,
I am not sure that the slip rings have anything to do with it, I just cleaned mine and replaced the brushes while I was in there. I guess it is possible it could play into it as the genset is searching for a frequency and voltage output which do change with resistance and RPM.
I doubt it is the control module, I would be that relay or governor issue.
Frustrating but not causing any real harm.
Windecker
|
|
|
07-30-2017, 09:29 PM
|
#11
|
Senior Member
Join Date: Oct 2013
Posts: 245
|
Will, just an FYI, I did clean the slip rings, replaced the brushes, and found a control board that I could try - no help - replaced the actuator (interestingly the new one ohmed out the same as the old one) and it runs rock steady now.
Thanks,
Kurt.
__________________
99 Executive 38 M11 450
|
|
|
07-31-2017, 06:47 AM
|
#12
|
Senior Member
Join Date: Dec 2011
Location: Logan Indiana (Near Cincinnati Ohio)
Posts: 755
|
Well that is good news! I guess it is just not a common problem, either that or folks don't care or notice.
Glad you got going for less than $15K (replacement).
Windecker
Quote:
Originally Posted by Kurt Averill
Will, just an FYI, I did clean the slip rings, replaced the brushes, and found a control board that I could try - no help - replaced the actuator (interestingly the new one ohmed out the same as the old one) and it runs rock steady now.
Thanks,
Kurt.
|
|
|
|
10-01-2019, 10:09 AM
|
#13
|
Senior Member
Join Date: Jun 2018
Location: Blairsville, GA
Posts: 218
|
Hi Everyone,
I am having a similar problem with my Onan 12,500 Isuzu generator. It surges for a while, but then shuts itself off. It used to stay on a lot longer (hours), but has gradually reduced the amount of time it takes before s shuts itself off. Now it's down to minutes.
I didn't notice anyone saying that theirs was shutting off. Any idea of where I should start?
__________________
2002 Monaco Signature Triple Crown
- been RVing since Aug, '18
|
|
|
10-01-2019, 11:48 AM
|
#14
|
Senior Member
Join Date: Jun 2018
Location: Blairsville, GA
Posts: 218
|
Never mind! We got enough panels off to see a piece of belt lying on the base/floor. Looks like it's not getting coolant circulated. That makes things a little easier (and not that expensive).
__________________
2002 Monaco Signature Triple Crown
- been RVing since Aug, '18
|
|
|
|
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|